Keysigning @ DebConf16

Where?

As part of the 17th Debian Conference in Cape Town, South Africa there will be OpenPGP (pgp/gpg) keysignings.

When?

The time and venue of a discussion/information session about the keysigning will be announced during DebConf16 in particular and modern cryptography in general. It may be followed by a number of keysignings of small groups of people.

What is keysigning and why do it

A keysigning party or meeting is a get-together of at least two individuals who use the PGP encryption system with the purpose of allowing them to sign each others keys. Keysigning parties serve to extend the web of trust (WoT) to a great degree. A useful metric of the WoT is the mean shortest distance (MSD) of a key.

Please read chapters one and two of the GnuPG Keysigning Party HOWTO (note: we are doing the party differently, so the other chapters do not apply completely).

Don't you have a strong key yet?

The Debian Project has moved to GPG keys with stronger ones using SHA256 or better. Please read:

How will the keysigning happen?

The keysignings will be based on the Efficient Group Key Signing Method by Len Sassaman and Phil Zimmermann which is a protocol to do keysignings in a way that is faster than the way many people may be familiar with.

The deadline has now passed. If you haven't submitted your keys yet, it's too late to get your keys on the list. It's not, however, too late to participate altogether. Bring paper slips or business cards with your gpg fingerprint.

The keysigning steps follow.

Please note that having multiple keys isn't a requirement. If you have one key to be signed, adjust the examples below from two keys to just one key.

Revoke all non-reacheable or no longer valid uids.

Update GnuPG to use SHA2 in preference to SHA1. Use error's gpg.conf file (see above) or read the information under "Update ~/.gnupg/gpg.conf" at https://keyring.debian.org/creating-key.html. Don't forget to update ~/.caff/gnupghome/gpg.conf as well, if you use caff for signing keys, otherwise your signatures will be SHA1.

Cross sign your keys and upload them to a key server, if you haven't done so yet.

Example with two keys 0xfedcba9876543210 and 0x0123456789abcdef and uploading to a key server:

Send your ascii armored, cleaned, minimized and clear-signed public keys to anibal@debian.org no later than 23:59 UTC/GMT/Zulu on Tuesday 21 June 2016. Multiple cross-signed keys per armor are just fine. The signatures will prove the owner of the keys controls the private keys.

Please check that your version of gpg does support the export-clean option.

Please do not encrypt your email.

Please do not send attachments.

Please do not encode your email.

Example with two keys 0xfedcba9876543210 and 0x0123456789abcdef, signature is made with both keys 0xfedcba9876543210 and 0x0123456789abcdef:

On Wednesday 22 June 2016 you will be able to fetch the complete keyring (ksp-dc16.gpg.bz2) with all the keys that were submitted along with a text file (ksp-dc16.txt) giving the fingerprint of each key on the ring.

At https://people.debian.org/~anibal/ksp-dc16/ both the keyring and text files will have corresponding files with their SHA256 checksums. The SHA256 files will be signed with public key 0xc6045c813887b77c2dff97a57c56acfe947897d8, which can be downloaded from keyring.debian.org or db.debian.org.

To verify the signature of the SHA256 files, download anibal's key from db.debian.org, e.g.:

finger anibal/key@db.debian.org | gpg --import

And then run gpg with the verify option (using ksp-dc16.txt.sha256.asc as an example):

gpg --verify ksp-dc16.txt.sha256.asc

Verify that the fingerprints of your keys in ksp-dc16.txt are correct. Also compute the SHA256 hash of ksp-dc16.txt. One way to do this is with sha256sum invoked as follows:

sha256sum ksp-dc16.txt

Bring to DebConf the hash you computed and a hardcopy of ksp-dc16.txt.

It is very important that you have verified at home the fingerprints of your keys on the hardcopy.

It is also very important that you have computed the hash at home.

The SHA256 hash of ksp-dc16.txt will be announced during the discussion/information session. Verify that the hashes match what you computed. This guarantees that all participants are working from the same list of keys.

During DebConf, look for keysigning participants during the conference.

For each participant:

Compare the hash you computed with the other participant (it will be recited loudly).

Ask if the other participant's gpg fingerprints on the hardcopy are correct.

Verify each other's identity by checking preferably a passport or, alternatively, some other form of government issued ID. Please don't show very old, doubtful or easy-to-fake documents as people will not sign your key if you do so.

If you are satisfied with the identification, mark on your hardcopy that the other participant's gpg fingerprints are correct and the other participant has been identified.

Later that evening, or perhaps when you get home, you can sign the keys in ksp-dc16.txt which you were able to verify and identify.

Please use caff to sign keys, one of the scripts of pgp-tools. The scripts are also available as the debian package signing-party.

Thanks

Special thanks goes to Benjamin Mako Hill who provided the scripts and text used at DebConf4, Peter Palfrader who provided the scripts and text used at DebConf3 and LinuxTag (2003 and 2004) whose reuse made putting together this keysigning easy and possible.